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10.06.16 St Johnston lab probes spindle orientation in fly wing epithelium using live imaging

last modified Jun 14, 2016 09:13 AM
Live imaging in this Development paper by Dan Bergstralh et al. reveals fine details of dividing cells in the Drosophila wing disc to show that orientation of mitotic spindle does not require the protein Pins.
10.06.16 St Johnston lab probes spindle orientation in fly wing epithelium using live imaging

A normally-oriented division in a pins mutant mitotic clone

Pins is not required for spindle orientation in the Drosophila wing disc

Bergstralh DT et al. (2016) Development Jun 10. pii: dev.135475. [Epub ahead of print.]


In animal cells, mitotic spindles are oriented by the dynein/dynactin motor complex, which exerts a pulling force on astral microtubules. Dynein/dynactin localization depends on Mud/NUMA, which is typically recruited to the cortex by Pins/LGN. In Drosophila neuroblasts, the Inscuteable/Baz/Par-6/aPKC complex recruits Pins apically to induce vertical spindle orientation, whereas in epithelial cells, Dlg recruits Pins laterally to orient the spindle horizontally. Here we investigate division orientation in the Drosophila imaginal wing disc epithelium. Live imaging reveals that spindle angles vary widely during prometaphase and metaphase, and therefore do not reliably predict division orientation. This finding prompted us to re-examine mutants that have been reported to disrupt division orientation in this tissue. Loss of Mud/NUMA misorients divisions, but Inscuteable expression and aPKC, dlg and pins mutants have no effect. Furthermore, Mud localizes to the apical-lateral cortex of the wing epithelium independently of both Pins and cell cycle stage. Thus, Pins is not required in the wing disc because there are parallel mechanisms for Mud localization and hence spindle orientation.

These results reveal a surprising diversity in epithelial tissue development.


Image is Figure 4B in the paper, reproduced under license CC BY 3.0.

Further information from the St Johnston lab.

Studying development to understand disease

The Gurdon Institute is funded by the Wellcome Trust and Cancer Research UK to study the biology of development, and how normal growth and maintenance go wrong in cancer and other diseases.